Add useUnfortunateSynchronousResizeMode to tests that need it.

I am ready to flip the flag in Content Shell, so need to
start using the flags (no-ops for now) in tests.

R=eseidel@chromium.org, eseidel
BUG=309760

Review URL: https://codereview.chromium.org/52803005

git-svn-id: svn://svn.chromium.org/blink/trunk@161086 bbb929c8-8fbe-4397-9dbb-9b2b20218538